Pneumatically operated gripper for bottle transferring apparatus

ABSTRACT

D R A W I N G A GRIPPER FOR BOTTLES COMPRISING A PLURALITY OF DOWNWARDLY EXTENDING GRIPPER FINGERS INTEGRALLY SECURED TO A BASE MEMBER MADE OF RESILIENT PLASTIC. THE BASE MEMBER CONSTITUTES A PISTON WHICH IS SURROUNDED BY A SLEEVE HAVING A CONICAL SURFACE ADJACENT THE LOWER END THEREOF WHICH COOPERATES WITH THE GRIPPER FINGERS IN SUCH A WAY THAT UPON AN UPWARD MOVEMENT OF THE SLEEVE THE GRIPPER FINGERS ARE MOVED INWARDLY TO GRIP THE BOTTLE NECK WHILE A DOWNWARD MOVEMENT OF THE SLEEVE WILL RELEASE THE GRIPPER FINGERS SO THAT THEY WILL BE MOVED OUTWARDLY DUE TO THEIR RESILIENCY TO RELEASE THE BOTTLE NECK.

Jan. 12, 1971 E. THOMA PNEUMATICALLY OPERATED GRIPPER FOR BOTTLE TRANSFERRING APPARATUS Filed Sept. 25, 1969 2 Sheets-Sheet l JNVEN TOR. 671, 90 RAM/4 Jan. 12, 1971 Filed Sept. 25, 1969 E. E. THOMA PNEUMATICALLY OPERATED GRIPPER FOR BOTTLE TRANSFERRING APPARATUS 2 Sheets-Sheet 2 5 a Fig\3 3&1

INVENTOR.

United States Patent 3,554,594 PNEUMATICALLY OPERATED GRIPPER FOR BOTTLE TRANSFERRING APPARATUS Ernst Erwin Thoma, Steppach, Germany, assignor to Certus Maschinenhau GmbH, Augsburg, Germany, a corporation of Germany Continuation-impart of application Ser. No. 698,776, Jan. 18, 1968. This application Sept. 25, 1969, Ser. No. 861,129 Claims priority, application Austria, Sept. 30, 1968, A 9,513/68 Int. Cl. B66c 1/54 US. Cl. 294-90 Claims ABSTRACT OF THE DISCLOSURE A gripper for bottles comprising a plurality of downwardly extending gripper fingers integrally secured to a *base member made of resilient plastic. The base member constitutes a piston which is surrounded by a sleeve having a conical surface adjacent the lower end thereof which cooperates with the gripper fingers in such a way that upon an upward movement of the sleeve the gripper fingers are moved inwardly to grip the bottle neck while a downward movement of the sleeve will release the gripper fingers so that they will be moved outwardly due to their resiliency to release the bottle neck.

CROSS REFERENCE TO A RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 698,776, filed Jan. 18, 1968.

This invention relates to a pneumatically operated gripper for bottle packers comprising several gripper fingers for gripping the bottle head, a wedge-shaped control member for moving the fingers radially inwardly into a gripping position, and a piston-cylinder unit in which one part supports the gripper fingers and the other part is connected to the control member.

One previously known gripper (German DAS No. 1,027,126) of this general type has two oppositely positioned gripper fingers, each of which is constructed as a double-armed lever and is pivoted to a part connected to the cylinder. A wedge-shaped member connected to the piston by a piston rod can, as soon as the piston is subjected to compressed air, be wedged between the upper lever arms of both gripper fingers which causes the lower lever arms to move toward one another and to grip the bottle head. If the compressed air is removed, the piston and thus the wedge-shaped member moves upwardly by the spring force. A further annular spring connecting the ends of the upper lever arms will then urge said upper lever arms toward each other which results in a spreading apart of the lower lever arms to a bottle receiving position. Said known pneumatically operated gripper, however, is relatively complicated in structure and thus expensive. It also is relatively large and thus heavy considering that several of such grippers are arranged on one gripper frame for lifting a packing unit. The gripper fingers, as well as the wedge-shaped guide members, can be made only of metal which on one hand results in a serious wear and on the other hand can damage the bottle. Furthermore, the bottle may not always be properly centered by the cooperating gripper fingers and thus can lead to considerable interference in bottle packers.

The purpose of the present invention is to construct a pneumatically operated gripper which is simpler in design and accordingly less expensive to manufacture, which results in a reduction in wear and with respect to which each bottle is properly centered so that it can be gripped satisfactorily.

T o attain said purpose, the invention provides that the circularly arranged gripper fingers have a common base member and are made of a single piece resilient plastic. Said base member comprises or is connected to the piston of an air cylinder system, and a sleeve is provided as a control member positioned concentrically to the gripper fingers, movable axially with respect to said fingers and comprises or is connected to the cylinder of said air cylinder system. Said sleeve provides at its lower end a downwardly inclined conical surface on which the lower ends of the gripper fingers are supported so that they are moved radially inwardly with respect to the base member to a gripping position upon an upward movement of the sleeve and due to their resiliency are moved radially outwardly into a nongripping or bottle receiving position upon a downward movement of the sleeve.

The new gripper has a specially simple structure. The gripper fingers and the base member comprise an integral component made of resilient plastic and can accordingly be manufactured inexpensively, for example, by molding: Jointed connections are not used and all gripper fingers can be connected to the base member so that only said base member must be connected to, or function as, the piston. Due to the circular arrangement of the gripper fingers, the bottle head is gripped around the periphery thereof so that the bottle is centered correctly with respect to the gripper. The gripper position determines the bottle position and for this reason, several bottles can be lowered in an exactly centered position into the boxes provided for same. Furthermore, the new gripper results in only little wear because said gripper has no joints and the only friction involved is with respect to the sleeve cooperating with said fingers and this is small even if said sleeve is made of such material as metal. The gripper fingers being made of plastic have the added advantage that the bottle head cannot be damaged.

Further advantages and details of the invention are disclosed in more detail hereinbelow in connection with the embodiments illustrated in the drawings in which:

FIG. 1 is a longitudinal central sectional view illustrating the two positions of the cylindrical sleeve;

FIG. 2 is a fragmentary central sectional view of a further embodiment; and

FIG. 3 is a sectional view taken along the line IIIllI of FIG. 2.

In FIG. 1, the gripper is identified by the reference number 1. Several of such grippers, for example twelve or twenty can be arranged on one vertically movable gripper frame 2 for the packing and unpacking of a corresponding number of bottles. The gripper comprises a base member 4 and several gripper fingers 3, for example ten, integrally secured to and circularly arranged on the base. Slots 5, which are provided between the gripper fingers 3, make it possible that the fingers, as this will be described hereinbelow, can be moved radially inwardly. The gripper finger 3 and base member 4 are made of a resilient plastic, which is for example known as Hostaform-C (acetal-copolymer) or Delrin (plastic made by polymerization of CH O, free of H 0). The base member 4 can be connected to an air-operated piston or as it is advantageously shown in the illustrated embodiment, is constructed as a piston and has a seal ring 6 mounted thereon. A sleeve 7 is sleevably mounted over the base 4 and seal ring 6 and is movable axially with respect to the base 4 and fingers 3 and functions as a control member. Said sleeve can be connected to an air cylinder or can advantageously be constructed as a cylinder itself as in the illustrated embodiment. Said sleeve comprises in its lower portion a downwardly inclined conical surface 8 which cooperates with the lower ends 3a of the gripper fingers 3. The cylindrical sleeve 7 is closed at its upper end by a cover 9, said cover being sealed with respect to the piston rod 11 by a seal ring 10. A flange 13 of an intermediate sleeve 14 limits the upward movement of the cylindrical sleeve 7 in case that no bottle is being gripped.

The base member 4 is secured to the piston rod 11 by means of a nut 15. The piston rod 11 can be of a hollow construction for the purpose of admitting air through the center thereof. The piston rod 11 is advantageously movable in an upward direction axially against the force of spring 17 with respect to the gripper frame 2. Said movability is provided so that each gripper upon a lowering of the gripper frame 2 can move slightly upwardly so that all grippers will be supported equally on tops of bottles having varying heights.

The coiled spring 17 is sleevably mounted over the piston rod 11 and is supported at one end on the gripper frame 2 and on the other end on the cover 9 of the cylindrical sleeve 7. Thus, the coiled spring 17 fulfills two functions, namely it is used for a resilient support of the entire gripper 1 with respect to the gripper frame 2 and it is used to return the cylinder 7 to the bottle receiving position as will be described in detail hereinbelow.

In order to facilitate insertion of the bottle top between the gripper fingers 3 and at the same time prevent an inward bending of the gripper fingers 3, the cylindrical sleeve has at its lower edge an upwardly inclined conical surface 18. The smallest diameter D of the surface 18 should thereby be at least the same size or smaller than the inner diameter of the gripper finger projections 3a when in the bottle receiving position as shown in the right side of the drawing.

The new gripper operates in the following manner:

The left side of the drawings shows the new gripper 1 in the bottle gripping position. The right side of the drawing shows the gripper in the bottle receiving position. When in the bottle receiving position, the gripper frame 2 with its grippers 1 provided thereon is lowered onto the top K of the bottles until the nut 15 comes to rest on the bottle top. Upon further lowering of said gripper frame 2, the spring 17 is slightly compressed and thus engagement of the gripper on the bottle head is assured. Compressed air is then fed into the cylinder chamber 17 through the hollow piston rod 11 which causes the cylindrical sleeve 7 to move upwardly. The conical surface 8 also moves upwardly to engage the lower ends 3a of the gripper fingers 3 to hereby move the fingers 3 radially inwardly until they snugly engage the bottle neck. Since the gripper fingers 3 surround the bottle head from all sides and since said bottle head is engaged with the nut 15, the bottle is positioned coaxially of the gripper 1 which is advantageous for its being placed in a desired box. After the bottle is moved to the desired location, the comprossed air is removed and the cylindrical sleeve 7 is moved downwardly by the compressed spring 17. The gripper fingers 3 will move radially outwardly due to their elasticity to thereby free the bottle head.

As one can understand from the above description, the most important parts of the new bottle gripper each have two functions which not only reduces the number of parts but also the weight of the entire gripper. The base member 4 is used both for holding the gripper fingers 3 and as a piston. The sleeve 7 is used both as a control member for the grippers fingers and as a guiding and centering device for the bottle head and finally also as an air cylinder. The same is true for spring 17 which is provided for biasing the entire gripper assembly to the nongripping position.

FIGS. 2 and 3 show another advantageous embodiment. The parts shown there, which in their function correspond to the parts of the embodiment first described, have primed reference numerals. In contrast to the embodiment first shown, however, on the inside of the cylindrical sleeve 7 guide ribs 20 are provided, extending upwardly in the axial direction from the inner edge 21 of the entry tfunnel 18 and the channels 22, in which the gripper fingers 3" are arranged, are formed between the guide ribs. For this purpose, the slots 5', provided between the gripper fingers 3' are widened in comparison with the first embodiment. The lower ends 3a of the gripper fingers also bear on guide surfaces 8', corresponding to those of the first embodiment example. The diameter of the inner edge 21 and hence also the diameter of the inner guide surfaces 20a of the guide ribs is equal to or, as shown in the drawing, somewhat less than the internal spacing of the lower ends 3a of the gripper fingers 3' in the non-gripping position. In this way, the lower end 3a of the gripper fingers 3 in the non-gripping position are situated radially outside the inner guide surfaces 20a of the guide ribs 20, so that when the gripper is placed over the bottle, or when the bottle is set down by the bottle head, the gripper fingers are prevented from coming into contact more particularly with the sharp-edged metal crown cork. This not only increases the life of the fingers, but it maks it practically impossible for the bottle head to be caught on any part of the gripper when the latter is being placed over the bottle, or also when the bottle is being set down. In FIG. 3 of the drawing the gripper fingers are shown in the n0n-gripping position in the right-hand half of the figure, and in the gripping position in the left-hand half.

For inexpensive production of the cylindrical sleeve 7, it is advantageously made of the same or a similar plastic to the gripper fingers.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pneumatically operated gripper for bottle packers comprising several circularly arranged fingers for gripping the bottle head, a control member for moving the fingers radially inwardly into a gripping position and a piston-cylinder unit in which one part supports the gripper fingers and the other part is connected to the control member, said circularly arranged fingers having one common base member and being made of a one-piece resilient plastic which is related to the pistion, said control member comprises a sleeve and includes means defining said cylinder, said piston being slidingly and sealingly received in said cylinder to permit a pneumatic operation of said piston, said sleeve being positioned concentrically of the gripper fingers and being movable axially with respect to said fingers and being fixedly connected to said cylinder, the lower end of said sleeve having a downwardly inclined conical surface on which the lower ends of the gripper fingers are supported, said piston being movable relative to said cylinder to move said inclined conical surface relative to said gripper fingers so that said fingers will engage said conical surface and be moved radially inwardly into a gripping position with respect to the base member upon a relative movement in one direction and will be moved radially outwardly into bottle receiving position due to their resiliency upon a relative movement in the opposite direction.

2. A gripper according to claim 1, wherein said base member defines said piston and is movably guided in said cylinder unit.

3. A gripper according to claim 1, including a piston rod fixedly secured to said piston, said cylinder unit sealingly engaging said piston rod.

4. A gripper according to claim 3, wherein said piston rod is of a hollow construction to permit the admission of compressed air into said cylinder unit.

5. A gripper according to claim 3, wherein said piston rod includes a spring for resiliently urging said piston rod axially with respect to a gripper frame supporting several of said grippers.

6. A gripper according to claim 5, wherein said spring concentrically surrounds said piston rod and is supported at one end on said gripper frame and at the other end on said sleeve and is used for returning said sleeve to said bottle receiving position.

7. A gripper according to claim 1, wherein said sleeve has an upwardly inclined conical surface adjacent the lower edge thereof.

8. A gripper according to claim 7, wherein the smallest diameter of said conical surface is equal to or smaller than the inner diameter of said gripper fingers when same are in said bottle receiving position.

9. A gripper according to claim 1, including guide ribs mounted on the inside of said sleeve extendingupwards References Cited UNITED STATES PATENTS 2,236,761 4/1941 Nichols 29486.31X 2,252,767 8/1941 Hudson 29486.31X 2,709,617 5/1955 Lang 29486.3X 3,108,835 10/1963 Rowekamp 2949O in an axial direction from the lower edge of the conical 15 EVON BLUNK, Primary Examiner R. S. GAITHER, Assistant Examiner 

